1. Wladimir Lyra California State University, Northridge
Fitting a snowline at 40AU at V883Ori
Wladimir Lyra
California State University, Northridge
Felipe Alarcón (Universidad de Chile, University of Michigan),
Simon Casassus (Universidad de Chile)
Lucas Cieza (Universidad Diego Portales)
Sebastian Perez (Universidad de Chile)
ExSoCal, Sep 18th, 2018

2. Felipe Alarcon
Michigan
Los
Angeles
Santiago

3. V883Ori Class I protostar (Age ~0.5 Myr) (L * ~ 6 Lsun)
M* = 1.3 +/- 0.1 Msun
Mdisk ~ 0.3 Msun
d = 414 +/-7 pc
Ldisk = 400 Lsun
50AU
Cieza et al. (2016)

4. V883Ori
Cieza et al. (2016)

5. Extra source of heating needed
Measured
Passive disk
Cieza et al. (2016)

6. V883 Orionis is an FU Orionis star

7. Episodic Accretion – Loading a dead zone
0.1 AU
~30 AU
There should be a magnetized, active zone
and a non-magnetic, dead zone

8. Possible FU Ori triggers
Audard et al. (2014)

9. Signature of a snowline: Spectral index
Optically thin
ISM-ilke values
Banzatti et al. (2014)
Optically thick
blackbody emission
Cieza et al. (2016)

10. Signature of a snowline: Optical depth
Optically thick
Optically thin
T=105+/-11 K
(R ~ 40AU)
Cieza et al. (2016)

11. Snowline pushed outward during outburst
Cieza et al. (2016)

12. Chiang et al. (2001), Alarcon et al. (in prep)
The model
Stellar heating
Viscous heating
Effective temperature
Midplane temperature
Chiang et al. (2001), Alarcon et al. (in prep)

13. Alarcon et al. (in prep)

14. Viscous heating
Alarcon et al. (in prep)

15. Best fit
Alarcon et al. (in prep)

16. Cieza et al. (2016), Alarcon et al. (in prep)
Self-shadowing
Cieza et al. (2016), Alarcon et al. (in prep)

17. Conclusions First water snowline observed;
Brightness temperature needs active heating;
Fit consistent with accretional inner disk, passive outer disk;
Self-shadowing reproduced;
Episodic accretion is powering V883 Ori !
What is the mechanism???
Can we use it to study whatever is causing it?
Gravitational instability?
Magnetorotational instability?
Planet?
All of the above?